body {
  background-color: #f4f4f4;
}
/* header 部分开始 */
.header {
  height: 60px;
  line-height: 60px;
  padding: 0 20px;
  overflow: hidden;
  background-color: #fff;
}
.logo {
  font-size: 0;
  margin-right: 30px;
}
.logo img {
  height: 60px;
  vertical-align: middle;
}
.nav li {
  float: left;
  margin-right: 20px;
}
.nav li:hover {
  color: #33aef0;
}
.search {
  position: relative;
  padding-top: 10px;
  margin-left: 20px;
}
.search input {
  border: none;
  width: 180px;
  border-bottom: 1px solid #000;
}
.keyword {
  position: absolute;
  left: 50%;
  width: 120px;
  margin-left: -70px;
  bottom: 10px;
  text-align: center;
}
.keyword span {
  font-size: 12px;
  background-color: #ccc;
  padding: 5px 10px;
  border-radius: 15px;
  cursor: pointer;
}
.keyword span:hover {
  color: #33aef0;
}
.icon-icon-test {
  position: absolute;
  right: 15px;
  bottom: 10px;
  cursor: pointer;
}
.r-btn {
  height: 60px;
}
.r-btn span {
  margin: 0 10px;
  font-size: 14px;
  cursor: pointer;
}
.r-btn span:hover {
  color: #33aef0;
}
.r-btn img {
  margin: 0 20px;
  height: 40px;
  border: 1px solid transparent;
  vertical-align: middle;
  border-radius: 100%;
  cursor: pointer;
}
.r-btn img:hover {
  border: 1px solid red;
}
/* header 部分结束 */
/* main 部分开始 */
.content {
  width: 1200px;
  margin: auto;
  padding: 20px 0;
  /* background-color: green; */
  min-height: 600px;
}
.banner {
  background-color: #fff;
  font-size: 0;
  overflow: hidden;
  border-radius: 20px;
}
.l-category {
  width: 220px;
  height: 450px;
  background-color: #0c0c13;
  opacity: .9;
  color: #fff;
  padding: 20px 0;
}
.l-category li {
  padding: 0 20px;
  font-size: 14px;
  line-height: 60px;
}
.l-category li:hover {
  background-color: #fff;
  color: #000;
  cursor: pointer;
}

.l-category li::after {
  content: ">";
  display: block;
  float: right;
}
.r-banner a {
  display: block;
  position: relative;
}
.r-banner a::before, .r-banner a::after {
  position: absolute;
  display: block;
  content: "";
  width: 27px;
  height: 44px;
  top: 50%;
  margin-top: -22px;
}
.r-banner a::before {
  background: url('../img/prev.png') no-repeat center;
  left: 20px;
}
.r-banner a::after {
  background: url('../img/next.png') no-repeat center;
  right: 20px;
}
.course {
  padding: 30px 0;
}
.title {
  padding: 20px 0;
  width: 180px;
  margin: auto;
  text-align: center;
}
.title h2 {
  padding-bottom: 10px;
  border-bottom: 2px solid red;
  font-size: 18px;
  font-weight: 700;
}
.title p {
  padding-top: 10px;
}
.course-item {
  width: 268px;
  overflow: hidden;
  margin-right: 40px;
  background-color: #fff;
}
.course-item:last-child {
  margin-right: 0;
}
.course-item img {
  width: 100%;
}
.course-item h3 {
  word-break: break-all;
  line-height: 24px;
  padding: 0 10px;
}
.level, .person {
  line-height: 30px;
  padding: 0 10px;
}
/* main 部分结束 */
.footer {
  height: 144px;
  line-height: 144px;
  text-align: center;
  background-color: #fff;
  /* background-color: yellow; */
}